HOW COILS CALCULATES CIRCUITS DURING A DESIGN ELABORATION
HOW COILS CALCULATES CIRCUITS DURING A DESIGN ELABORATION
The “Design” calculation mode of Coils software lets the user choose from a list of coils the best solution for a certain heat transfer and pressure drop requirement. But how does Coils generate the list of possible solutions? This will be discussed in the following document.
Basically the software performs an automatically calculation with all possible combinations of these three parameters:
- Number of rows
- Fin pitch
- Number of passes (or nr of tubes in series)
The first two parameters vary between the minimum and maximum values set by the user in the "Calculate" menu → "Design Profile".
The third parameter instead changes between 1 and 14 (*) and it’s used to calculate the number of circuits with the following formula:
Nr of circuits = (Nr of tubes per row * Nr of rows) / Nr of passes
Where the Nr of tubes per row is set by the user in the input parameters.
Here below you can see some examples:
Example 1 - Nr of Rows: 2
Fin Pitch: 2.1 mm
Nr of Tubes per Row: 32
In this situation, the number of circuits will vary from:
Nr of Passes: 1
Nr of Circuits = (32 * 2) / 1 = 64
To:
Nr of Passes: 14
Nr of Circuits = (32 * 2) / 14 = 4,57 = 5
Example 2 - Nr of Rows: 3
Fin Pitch: 2.1 mm
Nr of Tubes per Row: 32
In this situation, the number of circuits will vary from:
Nr of Passes: 1
Nr of Circuits = (32 * 3) / 1 = 96
To:
Nr of Passes: 14
Nr of Circuits = (32 * 3) / 14 = 6,85 = 7
Example 3 - Nr of Rows: 4
Fin Pitch: 2.1 mm
Nr of Tubes per Row: 32
In this situation, the number of circuits will vary from:
Nr of Passes: 1
Nr of Circuits = (32 * 4) / 1 = 128
To:
Nr of Passes: 14
Nr of Circuits = (32 * 4) / 14 = 9,14 = 9